Gunmen attacked a university radio station that has backed efforts to oust the Oaxaca state governor, as violence flared once more in protests that has driven many tourists from this colonial city.
The unidentified assailants fired rounds of gunfire into the station's windows while it was broadcasting late Saturday, the Oaxaca state government said in a news release. Nobody was hurt in the attack.
Witnesses said the attack was carried out by at least 10 assailants wearing ski masks, who drove up in three trucks and used automatic rifles.
The radio station at Oaxaca's university has supported protests aimed at ousting state governor Ulises Ruiz, who is accused of rigging the election to win office in 2004 and violently repressing dissent.
Teachers Union leader Enrique Rueda, who is one of the protest leaders, accused Ruiz of being behind the shooting.
Ruiz "has always responded to popular protests with aggression, threats, repression, and authoritarianism," Rueda said.
In a statement, Ruiz's office condemned the attack and said state government is trying to negotiate with the protesters. Ruiz belongs to the Institutional Revolutionary Party.
Dozens of protesters, including teachers, students and leftist activists, went with sticks and stones to guard the radio station.
With tensions still high on Sunday, an angry crowd abducted and beat two city law enforcement officials after a local radio station broadcast rumors that an activist had been arrested by municipal police.
The officers, who were blindfolded during the incident, were released a few hours later to the Red Cross.
Major protests erupted in Oaxaca in late June after police attacked a demonstration of striking teachers looking for a wage increase of about 20 percent.
Thousands of demonstrators have camped out in the Oaxaca City center, spraying buildings with revolutionary slogans, smashing the windows of a hotel and building makeshift barricades.
Business groups say the protests have reduced tourism by 75 percent and cost them more than US$45 million (euro36 million) in lost earnings. They are asking the federal government to intervene to stop the protests and declare Oaxaca a disaster area so they can get funds normally reserved for areas hit by hurricanes and earthquakes.
Associated Press Writer Ioan Grillo contributed to this report from Mexico City.